“…Fentanyl Derivatives: 2016 Conformation of fentanyl and its five derivatives using the IEF-PCM and SMD [ 1010 ]; 2017 GC-MS, QTOF-MS, MALDI-Orbitrap-MS, NMR and IR for confirmation of the presence of acrylfentanyl in seized material [ 1011 ]; identification of acrylfentanyl in powder from a seized capsule, analyses by QTOF-MS, MALDI-Orbitrap-MS, NMR and IR [ 1011 ]; discussion of the characteristics of the Swedish drug market for fentanyl-analogues in general and acrylfentanyl in particular and acrylfentanyl related deaths between April and October 2016 [ 1012 ]; review of chemical properties and the synthetic routes, analytical methodologies for the identification of acrylfentanyl, as well as the limited information on the biological properties [ 1013 ]; characterization of b cis and trans isomers of 3-methylfentanyl and its three analogues by GC/MS, LC/MS and NMR [ 1014 ]; GC/MS and LC/MS/MS detection of ocfentanil in heroin purchased off the dark web [ 1015 ]; 2018 review of Ocfentanil and Carfentanil [ 1016 ]; identification and characterization of fentanyl derivative N-(1-(2-fluorophenethyl)-4-piperidinyl)-N-(2-fluorophenyl)propionamide (2,2-difluorofentanyl) by HPLC-QTOF-MS, GC-MS, FTIR and NMR [ 1017 ]; review of various formulations of fentanyl, properties of fentanyl and its derivatives, and toxicity [ 1018 ]; review of fentanyl derivatives and uses [ 1019 ];…”